Water Management in Kirindi Oya Irrigation and Settlement Project in Sri Lanka

Water management in Kirindi Oya irrigation project is based on three important features of the managed system:

single-crop (rice) agriculture,

cascade implementation, i.e. part of the drainage flow coming from irrigated areas upstream is collected and stored in intermediate reservoirs,

connection to the sea, so
that a change of water use
in the area will have no adverse downstream effects.

In this context the goals of water management are to properly harvest rainfall and manage water issues during February-March (Maha season) to avoid losses, and to control water quality within the area. The target is to end the season saving maximum ammount of water
to supply the whole area during August-September (Yala) cultivation.

A GIS can be used in water delivery scheduling, allocation and operation to:

maintain connection with other models and data bases (i.e. hydraulics and hydrology).

As the first step of the implementation of Kirindi Oya GIS, an IDRISI-based

dashboard was developed to display the currently collected data on water
conditions and flows and the physical characteristics
of the watershed area (soils, water bodies, drainage, rain-fall).

The dashboard is installed in the managerís office. Further development will include building macro-procedures and linking specific models to develop a decision support platform. The latter will also address water quality issues in order to maintain salinity at a reasonable level by mixing water from various sources.